159
13
ANTENNA TUNER OPERATION
❍
If the tuner cannot tune the antenna, check the
following and try again:
• the correct antenna connector selection.
• the antenna connection and feedline.
• the untuned antenna SWR. (Less than 3:1 for the
HF bands; Less than 2.5:1 for the 50 MHz band)
• the transmit power. (8 W for the HF bands; 15 W for
the 50 MHz band)
• the power source voltage/current capacity.
If the tuner still cannot reduce the SWR to less than
1.5:1 after checking the above, perform the following:
• try manual tuning one or more times.
• adjust the antenna feedline length. (This is effective
for higher frequencies in some cases.)
Even if manual tuning does not match the antenna and
the tuner turns OFF the first time, it may match the an-
tenna the second time.
❍
Tuning a narrow bandwidth antenna
Some antennas, especially for the low bands, have
a narrow bandwidth. These antennas may not be
tuned beyond the edge of their operating bandwidth,
therefore, manually tune such an antenna as follows:
[Example]:
Suppose you have an antenna which has
an SWR of 1.5:1 at 3.55 MHz and an
SWR of 3:1 at 3.8 MHz.
q
Select 3.55 MHz and hold down [TUNER] for 1
second. to start manual tuning.
w
Select 3.80 MHz and hold down [TUNER] for 1
second to start manual tuning.
NOTES:
• The internal antenna tuner can only tune the HF
and 50 MHz bands— the 144 MHz, 430 MHz and
1200 MHz* bands cannot be tuned.
•
NEVER transmit without an antenna properly con-
nected to each antenna port in use.
• When 2 antennas are connected, select the an
-
tenna to be used with [ANT•METER].
• If the SWR is higher than about 1.5:1 when tun
-
ing farther than 100 kHz from an antenna’s pro-
grammed preset point, hold down [TUNER] for
1 second to start manual tuning.
• The internal tuner may not be able to tune in
the
AM mode. In such cases, hold down [TUNER] for
1 second to manually tune.
[TUNER]
■
Antenna tuner operation
The internal automatic antenna tuner automatically
matches the transceiver to the selected antenna. After
the tuner matches an antenna, the variable capacitor set-
tings are memorized as a preset point for each frequency
range (100 kHz steps). Therefore, when you change the
frequency range, the variable capacitors are automati-
cally preset to the memorized setting.
CAUTION: NEVER
transmit with the tuner ON when
no antenna is connected. This will damage the trans-
ceiver. Be careful of the antenna selection.
✔
For your convenience
When you purchase a brand-new antenna, or you
want to change the antenna settings, you can erase all
of the internal antenna tuner preset points with “Tuner
Preset Clear” in the Set mode. (p. 163)
D
Tuner operation
➥
Push [TUNER] to turn ON the internal antenna
tuner. The antenna is automatically tuned when the
antenna SWR is higher than 1.5:1.
• When the tuner is ON, “
” appears.
D
Manual tuning
Transmitting in SSB with a soft voice, the internal tuner
may not automatically tune correctly. In such cases,
manual tuning is helpful.
➥
Hold down [TUNER] for 1 second to start manual
tuning.
• A sidetone sounds, “
” blinks and the TX/RX indi-
cator (MAIN Band) lights red while tuning.
• If the tuner cannot reduce the SWR to less than 1.5:1
after 20 sec. of tuning, “
” disappears and the TX/
RX indicator (MAIN Band) goes out.
